This is an RF modulator replacement based on C0pperdragon’s for the shortboard Commodore 64 variant - 250469 with S-Video and audio output You'll need to desolder your current modulator, solder headers to your C64 taking care to align the sockets with the holes in the case. You need to be competent with a soldering iron and need a solder sucker and/or desoldering braid! See pawel Mendes’ GitHub page for more details the URL is shown on the underside of the PCB. NB You will need to configure J1,J2,J3 to enable the sound out the jack.
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